At A Glance
Noteworthy Characteristics
- Measured height (or length) and weight available to calculate body mass index.
- Physical activity assessed with accelerometers (2003-2006).
- Numerous other nutrition and health indicators obtained through physical examination, questionnaire, and assays.
- Established linkages with National Death Index, and linkages planned with Centers for Medicare and Medicaid Services, and Social Security Administration data sets.
- Dietary intake assessed through USDA’s What We Eat in America (WWEIA), the dietary component of NHANES from 2002 to the present. Beginning with the 2003-2004 data release, WWEIA, NHANES contains two 24-hour recalls (2002-present).
Website
http://www.cdc.gov/nchs/nhanes.htm
Purpose
To collect data about the health, nutritional status, and health behaviors of individuals in the United States (US).
Target Population
Civilian, noninstitutionalized individuals in the US; all ages.
Conducted
Began in 1999. Conducted continuously in 2-year cycles. Most recent cycle completed 2007-2008.
Sponsor
National Center for Health Statistics, Centers for Disease Control and Prevention, US Department of Health and Human Services
Special Note(s)
In 2012, the Centers for Disease Control and Prevention (CDC) will conduct a special survey on physical activity and fitness in children and adolescents. This survey, the NHANES National Youth Fitness Survey, will be fielded alongside the regular NHANES. The sample will consist of 1,500 children ages 3-15. Examination components will include body measurement (anthropometry), physical activity monitor (accelerometry), treadmill, lower body muscle strength, grip strength, modified pull-up, plank, gross motor skills, and a 24-hour dietary recall interview.
NHANES dietary intake data are collected using the US Department of Agriculture’s (USDA) dietary data collection instrument, the Automated Multiple-Pass Method (AMPM). The AMPM is a fully computerized method for collecting 24-hour dietary recalls. Learn more. The dietary intake data are processed at USDA using USDA’s Food and Nutrient Database for Dietary Studies (FNDDS). The NHANES dietary recall component is simultaneously released by NCHS and USDA. At USDA, the NHANES dietary intake component is referred to as What We Eat in America. Previously conducted nationally representative dietary surveys conducted by the USDA are:
1998 Continuing Survey of Food Intakes by Individuals (CSFII) Special Supplemental Children’s Survey
1994-1996 CSFII and Diet and Health Knowledge Survey (DHKS)
1989-1991 CSFII and DHKS
See Also:
NHANES III 1988-1994
Hispanic Health and Nutrition Examination Survey (HHANES), 1982-1984
NHANES II 1976-1980
NHANES I 1971-1975
Sampling
Sample Design
Cross-sectional survey.
Complex, stratified, multistage, probability sample representative of the civilian, non-institutionalized US population. Oversampling of specific age groups, racial/ethnic groups, and low-socioeconomic status populations. Learn more.
Sample Size
Target sample size is 10,000 individuals examined in each 2-year cycle.
Special Note(s)
NHANES has constructed various sample weights for single 2-year survey cycles to take into account survey non-response, oversampling, post-stratification, and sampling error. Learn more.
Key Variables
Demographic
| Name | Methods of Assessment |
|---|---|
| Age | Interview/questionnaire |
| Birth country (head of household) | Interview/questionnaire |
| Disability (hearing; movement/physical; vision) | Interview/questionnaire |
| Education level | Interview/questionnaire |
| Family size | Interview/questionnaire |
| Household income level and sources | Interview/questionnaire |
| Language spoken at home | Interview/questionnaire |
| Occupation (head of household) | Interview/questionnaire |
| Participation in welfare/food assistance programs (including reduced meals) | Interview/questionnaire |
| Race/ethnicity | Interview/questionnaire |
| Sex | Interview/questionnaire |
Diet-Related
| Name | Methods of Assessment |
|---|---|
| Attitudes toward health/diet | Interview/questionnaire |
| Availability of fruit, dark-green vegetables, salty snacks, low-fat milk, and soda/flavored drinks in home | Interview/questionnaire |
| Breast/formula/milk feeding | Interview/questionnaire |
| Factors influencing grocery shopping | Interview/questionnaire |
| Fat content of milk consumed | Interview/questionnaire |
| Food security | Interview/questionnaire |
| Frequency and types of meals away from home | Interview/questionnaire |
| Frequency of consumption of ready-made meals | Interview/questionnaire |
| Frequency of family meals at home | Interview/questionnaire |
| Frequency of home-cooked meals | Interview/questionnaire |
| Intakes of fruits and vegetables, fiber/whole grains, added sugars, dairy, calcium, red meat/processed meat | Dietary screener |
| Monthly grocery spending | Interview/questionnaire |
| Monthly spending on eating outside home, takeout/delivery, and food purchases at convenience stores | Interview/questionnaire |
| MyPyramid knowledge | Interview/questionnaire |
| Perceived health of diet | Interview/questionnaire |
| Salt use | Two 24-hour recalls |
| Special diet for health or weight loss | Interview/questionnaire |
| Supplement usage | Interview/questionnaire, 24-hour dietary recall |
| Total food and nutrient intake | Two 24-hour recalls |
| Use of food labeling | Interview/questionnaire |
| Vegetarianism | Interview/questionnaire |
Physical Activity-Related
| Name | Methods of Assessment |
|---|---|
| Cardiorespiratory fitness | Physical examination (ages 12-49 years) |
| Frequency and amount of time spent on vigorous and moderate physical activity | Interview/questionnaire |
| Frequency of physical activity (60 minutes+/day) | Interview/questionnaire |
| Sedentary activities (e.g., television, computer outside school, sitting) | Interview/questionnaire |
| Walking/bicycling for travel | Interview/questionnaire |
Weight-Related
| Name | Methods of Assessment |
|---|---|
| Height | Physical examination, interview/questionnaire (ages 8+ years) |
| Relative weight perception | Interview/questionnaire (ages 8+ years) |
| Skinfold thickness | Physical examination |
| Waist circumference | Physical examination |
| Waist/hip ratio | Physical examination |
| Weight | Physical examination, interview/questionnaire (ages 8+ years) |
| Weight history | Interview/questionnaire (ages 8+ years) |
| Weight loss attempts/strategies | Interview/questionnaire (ages 8+ years) |
Nutritional Status
| Name | Methods of Assessment |
|---|---|
| Nutritional biochemistry and hematology, blood lipids | Laboratory analyses on blood and urine samples |
Special Note(s)
All variables are not assessed in every 2-year cycle. Learn more about which variables are included in various cycles.
Data Access and Cost
Data Availability
Download public-use data from the NHANES website.
To protect the confidentiality of respondents, some data are restricted use. These data are available only through the NCHS Research Data Center. Learn more.
Cost
All public-use data are available free of charge.
Restricted-use data have charges associated with them, depending on the access mode, the number of survey cycles included, and other factors. Learn more.
Special Note(s)
Investigators must contact the NCHS Research Data Center to obtain restricted-use data. For a fee (which varies based on number of survey cycles analyzed and how data will be accessed), NCHS will create a data file and offer basic analytic support to researchers. Investigators must submit proposals to obtain these data (processing usually takes 6 to 8 weeks). Learn more about the proposal process and how the data can be accessed.
Geocode/Linkage
Geocode Variable(s)
County and state Federal Information Processing Standards (FIPS) codes, census block, census tract, latitude, and longitude. Geographic data are restricted use data and available only through the National Center for Health Statistics (NCHS) Research Data Center. Learn more.
Existing Linkages
NCHS has established linkages between the 1999-2008 NHANES data and the National Death Index.
In addition, it is planning linkages with:
• National food assistance program data
• Medicaid data
• Birth record data for the offspring of pregnant women in the 1999-2006 NHANES, and for children ages 6 to 10 years in the 2005-2010 NHANES.
Special Note(s)
A 2003 NHANES forum discussion provides useful background on NHANES linkage issues.
See the Data Access and Cost page for information about accessing restricted-use data through the NCHS Research Data Center.
Selected Publications
Diet-Related
Bachman JL, Reedy J, Subar AF, Krebs-Smith SM. Sources of food group intakes among the US population, 2001-02. Journal of the American Dietetic Association. 2008;108(5):804-814.
Food Surveys Research Group, US Department of Agriculture. What We Eat in America, NHANES.
Risk Factor Monitoring and Methods Branch, Applied Research Program, National Cancer Institute. Selected Intakes as Ratios of Energy Intake, US Population, 2001-04.
Physical Activity-Related
Mark AE, Janssen I. Dose-response relation between physical activity and blood pressure in youth. Medicine and Science in Sports and Exercise 2008;40(6):1007-1012.
Mark AE, Janssen I. Influence of bouts of physical activity on overweight in youth. American Journal of Preventive Medicine 2009;36(5):416-421.
Matthews CE, Chen KY, Freedson PS, Buchowski MS, Beech BM, Pate RR, Troiano RP. Amount of time spent in sedentary behaviors in the United States, 2003-2004. American Journal of Epidemiology 2008;167(7):875-881.
Troiano RP, Berrigan D, Dodd KW, Mâsse LC, Tilert T, McDowell M. Physical activity in the United States measured by accelerometer. Medicine and Science in Sports and Exercise 2008;40(1):181-188.
Weight-Related
Flegal KM, Carroll MD, Ogden CL, Curtin LR. Prevalence and trends in obesity among US adults, 1999-2008. JAMA 2010;303(3):235-241.
Ogden CO, Carroll MD, Flegal KM. High body mass index for age among US children and adolescents, 2003-2006. JAMA 2008;299(20):2401-2405.
Resources
Analytic Guidelines
http://www.cdc.gov/nchs/nhanes/nhanes2003-2004/analytical_guidelines.htm
Documentation/Codebook(s)
Listserv
The NHANES listserv provides a mechanism for disseminating information about NHANES activities, products, and release dates.
Tutorial(s)
The Continuous NHANES Tutorial is designed to help users learn how to perform general analyses using the Continuous NHANES. Users can browse through different modules to gain insight into NHANES data.
The NHANES Dietary Web Tutorial explains the steps of conducting an analytical project from beginning to end, with examples of many common analytic procedures. Relevant dietary data information and nuances, tips, and explanations for SAS or SUDAAN programs; downloadable sample program code; and analytical guidance are organized and integrated into different modules and tasks to facilitate this learning process.
